HOTP
A counter-based one-time password algorithm defined by RFC 4226. Alongside TOTP, it uses an incrementing counter rather than a timestamp as input.
Timeline (last 90 days)
TOTP is defined in RFC 6238 and is a time-dimension extension of HOTP (RFC 4226); it is computed by dividing the current Unix timestamp by the time step to obtain a counter C, then computing HMAC-SHA1(K, C), extracting a 31-bit integer via dynamic truncation, and taking the result modulo 10^6 to obtain a 6-digit verification code.
HOTP is a counter-based rather than time-based algorithm defined by RFC 4226.
TOTP is an evolution of HOTP (HMAC-Based One-Time Password, RFC 4226); HOTP uses an incrementing event counter, and TOTP replaces it with the current timestamp.
All Facts (3)
TOTP is defined in RFC 6238 and is a time-dimension extension of HOTP (RFC 4226); it is computed by dividing the current Unix timestamp by the time step to obtain a counter C, then computing HMAC-SHA1(K, C), extracting a 31-bit integer via dynamic truncation, and taking the result modulo 10^6 to obtain a 6-digit verification code.
50%UnverifiedHOTP is a counter-based rather than time-based algorithm defined by RFC 4226.
50%UnverifiedTOTP is an evolution of HOTP (HMAC-Based One-Time Password, RFC 4226); HOTP uses an incrementing event counter, and TOTP replaces it with the current timestamp.
50%